Investigations on highly stable thermal characteristics of a dilute In0.2Ga0.8AsSb/GaAs doped-channel field-effect transistor

Abstract

This work reports for the first time a novel In0.2Ga0.8AsSb/GaAs heterostructure doped-channel field-effect transistor (DCFET) grown by the molecular beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the DCFET device has been effectively improved by introducing surfactant-like Sb atoms during the growth of the Si-doped InGaAs channel layer. The improved device characteristics include the peak extrinsic transconductance (gm, max) of 161.5 mS mm−1, the peak drain–source saturation current density (IDSS, max) of 230 mA mm−1, the gate–voltage swing (GVS) of 1.65 V, the cutoff frequency (fT) of 12.5 GHz and the maximum oscillation frequency (fmax) of 25 GHz at 300 K with the gate dimensions of 1.2 × 200 µm2. The proposed design has also shown a stable thermal threshold coefficient (∂Vth/∂T) of −0.7 mV K−1.